'86 305 TPI, completely stock. It starts up and runs OK on a chilly start in the morning. But after sitting out in the sun all day at work, it will barely run when it starts up. Idle will be unstable, and if you even just barely touch the gas, it immediately starts to stumble, pop, hesitate, etc. Then it starts running smoother again as soon as you let back off the gas. Once it starts getting up to temp, it runs OK again. It does not set a code when it does this.

Also, the car does not usually run perfect. There is almost always a light hesitation off idle, and throttle response is not that great. It's not bad, but I know it should be better.

All the basics have been checked out and adjusted if needed. Fuel pressure has always tested good, but it was always running well at the time.

I'm thinking it might be a bad fuel pump. Anyone else agree, or have a better idea?

 

Id check your Mass air flow stuff. and give it a good tune up. more than likley an air/fuel mixture-vaccum problem

 

Tune up has been done, MAF stuff checked out and swapped with my other '86 just to be safe. It has also been thoroughly tested for vacuum leaks with a fogger. EGR has also been deleted since it had a tendency of sticking open on a cold start.